The next platform war: Google play vs. Apple iTunes

FORTUNE — The consensus among analysts the day after Google’s GOOG jam-packed I/O keynote is that Apple AAPL doesn’t have much to fear from the hardware unveiled on Wednesday. The $299 Nexus Q mimics Apple TV but at three times the cost. The $199 Nexus 7 tablet is aimed at Amazon’s AMZN Kindle, not the iPad. And it’s going to take a cultural revolution to turn Google Glass — the company’s $1,500 augmented reality head mounted display — into a mass market line of fashion eyeware.

But there was one announcement that should give Apple pause: The rebranding of the Android Marketplace into Google play.

It’s no secret that the Android platform — despite its dominance in terms of smartphones sold — has been struggling to hold its own against Apple’s iTunes. Although Android has nearly caught up to Apple in the sheer number of available apps (650,000 vs. 600,000), in almost every other respect it trails far behind. iTunes users listen to more music, buy more apps, keep them longer, look at more ads, purchase more products and generate far more revenue ($1.9 billion in fiscal Q2 alone).

Some have argued that the most important announcement Apple made at its World Wide Developers Conference two weeks ago was that the company now has 400 million credit cards on file — double last year’s total and more than any other online retailer, including Amazon. Those 400 million accounts — and the billions of songs, movies, TV shows and books purchased with a single click and stored on millions of hard drives around the world — are the glue that makes the iTunes platform so sticky.

So it probably didn’t escape Cupertino’s notice that with its new name and new features, Google play looks an awful lot like iTunes: A one-stop virtual shopping mall for entertainment.

And it may not be an accident that 20 minutes after the end of Google’s presentation, Bloomberg ran a piece — sourced by “people with direct knowledge of the matter” — saying that Apple was getting ready to release an overhaul of iTunes that would mark, according to the story, “one of the largest changes to the world’s biggest music store since its 2003 debut.”

It was the closest thing we’re likely to get to an official Apple response to Google’s keynote. The fact that the famously bloated iTunes platform needed an overhaul and that Apple has been working on one is not news. 9to5Mac‘s Mark Gurman had the story (with screenshots) in April.

But timing of the leak — if that’s what it was — suggests that the game is now officially on. Let the next platform war begin.